[Tagging] Using relations to group highways

[Matthias Julius]

Alex Mauer <hawke at hawkesnest.net> writes:

> On 01/05/2010 01:32 PM, John Smith wrote:
>> Currently there is discussion on using relations to group segments of
>> a highway occurring:
>> 
>> http://trac.openstreetmap.org/ticket/2599
>
> In that ticket, you wrote: “we think administrative polygons should be
> used for custom highway shields, instead of trying to tell the rendering
> software explicitly which shield to use”
>
> How might this work?  Presumably there’s some idea of linking
> primary/secondary/tertiary each with an administrative level, using that
> to determine which of the administrative polygons applies to the route
> in question, and then deciding from there which shield to use.  Do I
> have it right?

This could be derived from the ref tag and administrative boundary.
"A 2" should get a different shield in Germany than in the UK.  Same
goes for "M 5" in Michigan or UK.

The road classification is not always linked to highway type.  In the
US a primary road can be a US or state highway for example and a US
highway mey be a primary, trunk or motorway.

Matthias